The subject of this patent application relates generally to atrial fibrillation, and more particularly to an atrial fibrillation detection system and associated methods of use configured for analyzing and identifying atrial fibrillation signs.
Applicant(s) hereby incorporate herein by reference any and all patents and published patent applications cited or referred to in this application.
By way of background, atrial fibrillation (“AF”) is an abnormal heart rhythm characterized by rapid and irregular beating, often starting as brief periods of abnormal beating and becoming longer and possibly constant over time. AF is associated with an increased risk of heart failure, dementia, and stroke. It is one of the most, if not the most, commonly sustained forms of arrhythmia, increasing in prevalence with the age of patients; from 0.5% at 40-50 years of age, to 5-15% at 80 years of age. Men are more often affected than women. The lifetime risk of developing AF is roughly 25% in those who have reached the age of 40.
AF usually progresses from short, rare episodes, to longer and more frequent attacks. Clinically, different types of AF are distinguished, based on the presentation and duration of the arrhythmia. Paroxysmal AF consists of self-terminating episodes, usually shorter than 48 hours. Persistent AF is present when an AF episode either lasts longer than 7 days or requires termination by cardioversion (either pharmacological or electrical). Long-standing persistent AF is considered so when it has lasted for more than 1 year. Permanent AF is said to exist when the presence of the arrhythmia is accepted both by the patient and the physician. In general terms, a patient is usually diagnosed from paroxysmal AF and as time goes on it will evolve to sustained forms of AF. The distribution of paroxysmal AF recurrences is not random, but clustered, and AF burden (the time ratio with and without AF) can vary markedly over months or even years in individual patients. Asymptomatic AF (silent AF) is common even in symptomatic patients, irrespective of whether the initial presentation was persistent or paroxysmal.
Rapid and irregular heart rates may be perceived as palpitations or exercise intolerance and occasionally may produce anginal chest pain (if the high heart rate causes ischemia). Other possible symptoms include congestive symptoms such as shortness of breath or swelling. The arrhythmia is sometimes only identified with the onset of a stroke or a transient ischemic attack (“TIA”). Additionally, AF episodes can self-terminate and the triggering situations of a new episode are not easily predictable. As such, it is not uncommon for a patient to first become aware of AF from a routine physical examination or ECG, as it often does not cause symptoms. It has been estimated that 7-day continuous ECG monitoring may document the arrhythmia in approximately 70% of AF patients. To process these long-term ECG signals, either real-time or offline, AF detection algorithms are needed. Thus, there is a need for systems and methods capable of detecting AF signs (i.e., able to distinguish between AF and non-AF rhythms) as early and accurately as possible, so that such patients may be promptly diagnosed and treated in order to effectively control the disease.
Aspects of the present invention fulfill these needs and provide further related advantages as described in the following summary.